Reentry Catheter and Method Thereof

ABSTRACT

The invention generally relates to method and apparatus for crossing an obstruction in a tubular member, and more particularly to a medical device method for crossing of a chronic occlusion in a subintimal or interstitial space of an artery.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/503,477, filed on Jun. 30, 2011, which is herebyincorporated by reference for all purposes as if fully set forth herein.

FIELD OF THE INVENTION

The invention generally relates to method and apparatus for crossing anobstruction in a tubular member, and more particularly to a medicaldevice method for crossing of a chronic occlusion in a subintimal orinterstitial space of an artery.

BACKGROUND OF THE INVENTION

Atherosclerosis is a common human ailment arising from deposition offatty-like substance, such as atheroma, or plaque on the walls of majorblood vessels. These deposits occur within the peripheral arterialsystem which feeds the limbs of the body and also occur within thecoronary arterial system which feeds the heart. These depositsaccumulate in localized areas, narrow the vascular lumen, and eventuallycausing restriction of normal blood flow. In some cases, the depositsresult in a chronic partial or total occlusion. Such restriction canlead to a serious health risk including critical limb ischaemia. Ifblood flow cannot be adequately restored through surgical orendovascular intervention and the probability of limb amputationincreases dramatically.

Until recently, chronic total occlusions have been treated by bypasswhich poses high procedural risks and is quite traumatic to the patient.Recently, catheter based intravascular procedures have been utilized.These techniques include step-by-step crossing of an occlusion usingExcimer laser atherectomy devices and methods, crossing the occlusionwith highly flexible and maneuverable guide wires, and other techniquesknown in the art. Once the lesion has been crossed, then standardendovascular devices such as laser atherectomy, angioplasty, stenting,and the like, can be used to enlarge the lumen and increase blood flowwithin the peripheral arterial system. These catheter-basedintravascular procedures are typically preferred since they are muchless traumatic to the patient, safer and cost-effective while deliveringcomparable long term vessel patency compared to more traumatic surgicalalternatives.

Before catheter-based treatments can be used, with the exception ofstep-by-step Excimer laser methods, the guide wire must first passthrough the total occlusion to provide access for the interventionalcatheter. Specifically, once a guide wire has crossed the occlusion, itcan then be used as a rail to support interventional catheters. In somecases, the physician can maneuver the guide wire through the totalocclusion establishing access. In many instances, the physicianencounters a calcified cap on the proximal end of the occlusion and isunable to maneuver the guide wire through the cap and across a calcifiedor fibrous lesion. In many cases, the guide wire inadvertentlypenetrates the subintimal space between the intimal layer and theadventitial layer of the blood vessel as the guide wire attempts tocross the lesion. Once in the subintimal space, it is difficult todirect the guide wire back into the vessel lumen making it nearlyimpossible to perform a catheter based intravascular procedure.

In one related art technique, Dr. Bolia developed a revasculatureprocedure as described in Recanalisation of femoro-popliteal occlusions:Improving success rate by subintimal recanalisation, Clinic Radiol,40:325, 1989, by exploiting the subintimal space where a guidewireenters the subintimal space between the intima and adventitia layers, issubsequently advanced to a point distal to the occlusion, and thenmaneuvered to re-enter or puncture the vessel layers to enter the truelumen of the vessel. Once the guide wire has traversed through thesubintimal layer and re-enters the true lumen of the vessel at a pointdistal to the occlusion, percutaneous balloon angioplasty is performedto restore blood flow through subintimal recanalization. This is ahighly skilled technique with a low to moderate success level ofconsistent re-entry at the physician's preferred location just distal tothe occlusion.

There are number of other related art catheters and methods for forminglateral penetrations through tissue to and from blood vessels past totalocclusions, some of these are described in U.S. Pat. Nos. 5,443,497;5,429,497; 5,409,019; 5,287,861; 6,231,546; 6,217,527; 6,506,178;6,221,049; 6,235,000; 6,511,458; 6,719,725; 7,004,173; and 7,179,270,all of which are incorporated by reference for teaching reentrycatheters, methods and for the purpose of written description andenablement requirements. These related art methods embody penetration ofa needle exiting through either a side port or through a distal port,the needle must be oriented properly to ensure that the needle, whendeployed, re-enters at a preferred location distal to the occlusion. Oneproblem with these methods is a tendency of the catheter to back out asa result of the moment imposed by force required to penetrate thesubintimal layers to gain access to the vessel true lumen. This isparticularly problematic in the presence of calcified lesions causing anincrease in the forces necessary for successful re-entry and, in manycases, requiring the physician to re-enter at a sub-optimal location.

SUMMARY OF THE INVENTION

The invention is directed to a medical device and method thereof thatsubstantially obviates one or more of the problems due to limitationsand disadvantages of the related art.

An advantage of the invention is the reduction in the forces required tocross the subintimal layer during device reentry into the true vessellumen due to the articulating cannula or sharp member.

Yet another advantage of the invention is the reduction in the overallrequired size of the device since a long rigid element is not needed atthe distal tip to support large reentry forces.

Still another advantage of the invention is improved stability andcontrol of the distal tip during deployment of the cannula orinterventional wire upon reentry from the subintimal space to the truevessel lumen thereby preventing against the device backing out orfurther separating the intima from the adventitia.

Yet another advantage of the invention is improved trackability andcontrol, thereby allowing a physician or operator to re-enter the truevessel lumen at their preferred location close to the distal end of thetotal occlusion.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, is toprovide a method for crossing an obstruction in a blood vessel. Themethod includes advancing a guide wire into an interstitial space of avessel. Next, a catheter is advanced into the subintimal space with theaid of the guide wire. This may be accomplished using a traditional overthe wire approach or using a rapid exchange catheter. For example, arapid exchange reentry catheter method and catheter is described in U.S.Patent Application No. 61/503,477, which is hereby incorporated byreference as if fully set forth herein.

In one embodiment, a second wire or the original wire in an over thewire configuration, is advanced down a central lumen of a reentry memberthat is configured to deploy through at least one distal port to gainaccess to a vessel true lumen from a subintimal space.

In a preferred embodiment, the operator activates the reentry memberthrough either a push or pull mechanism or the deployment of a balloonto direct the sharp from the subintimal space into the vessel lumen.Through this preferred embodiment, reentry into the true lumen of avessel is accomplished at a location immediately distal to the totalocclusion. It is noted that other locations may also be used forreentry. Preferably, the reentry member is configured to exit thelateral port and into the true lumen of the vessel from the subintimalspace prior to advancement of an intervention wire through the lateralport.

Another aspect of the invention is directed towards a catheter systemthat includes a catheter having a proximal end, a distal end, lateralport, and at least one lumen. At least one lumen extends longitudinallythrough at least the lateral port of the catheter. The catheter includesa reentry member which is configured to gain access to a vessel truelumen from a subintimal space. The reentry member is configured topenetrate the vessel layers adjacent to the distal port. In a preferredembodiment, the reentry member has one or more sharpened edge surfacesalong a distal portion of the cutting device. The reentry member isconfigured to have a hollow portion to receive an interventional guidewire.

Yet another aspect of the invention is directed towards a reentrycatheter for use in forming a pathway in an interstitial space of anartery. The reentry catheter includes a catheter body including aproximal end, a distal end, at least one lumen, and at least one port.An exchange port is arranged on at least a distal portion of thecatheter body and the exchange port includes at least one lumenconfigured to receive a guidewire and the catheter body is configured totrack over the guidewire to a treatment site. A reentry member isslidably arranged within the lumen of the catheter body and isconfigured to deploy through the catheter body port. In one embodiment,the reentry member is configured to deploy from a first location withinthe interstitial space of an artery to a second location within a truelumen of the artery upon application of a substantially eccentric forceto a distal portion of the reentry member.

Still yet another aspect of the invention is directed towards a reentrycatheter for use in forming a pathway in an interstitial space of anartery. The reentry catheter includes a catheter body having a proximalend, a distal end, at least one lumen, and at least one port. Anexchange port is arranged on at least distal portion of the catheterbody. The exchange port is configured to receive a guidewire and thecatheter body is configured to track over the guidewire to a treatmentsite. A reentry member having a proximal end, a distal end, at least onelumen is configured to be slidably positioned within the lumen of thecatheter body. The reentry member includes a portion having a sharpsurface to permit dissection of a portion of an artery. A tether iscoupled to a distal end portion of the reentry member and the reentrymember is configured to deploy through the at least one port from afirst location within the interstitial space of an artery to a secondlocation within a true lumen of the artery upon application of a forceto the tether.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 illustrates an exemplary side view of a reentry catheteraccording to an embodiment of the invention;

FIG. 2A illustrates an exemplary bottom-profile view of the reentrymember illustrated in FIG. 1;

FIG. 2B illustrates an exemplary side-view of the reentry memberillustrated in FIG. 1;

FIG. 2C illustrates an exemplary end-view of the reentry memberillustrated in FIG. 1;

FIG. 3A illustrates an exemplary side view of the reentry memberaccording to another embodiment of the invention;

FIG. 3B illustrates an exemplary end view of the reentry memberaccording to FIG. 3A;

FIGS. 4A-4B illustrate a mechanism for controlling a reentry memberaccording to another embodiment of the invention;

FIGS. 5A-5B illustrate a mechanism for controlling a reentry memberaccording to another embodiment of the invention;

FIGS. 6A-6B illustrate a mechanism for controlling a reentry memberaccording to another embodiment;

FIG. 7 illustrates an exemplary side view of a reentry catheteraccording to another embodiment of the invention; and

FIG. 8A-8H illustrates an exemplary method for using a medical device ofFIG. 1 and FIG. 7.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention generally relates to a method and system for crossing anobstruction in a tubular member, e.g., crossing a chronic totalocclusions in a blood vessel, and more particularly to a medical devicemethod for crossing of an occlusion in a subintimal or interstitialspace of an artery. Subintimal or interstitial region or space is at alocation beneath at least a portion of intima and preferably at alocation contained between the intima and the adventitia of the vessel.The terms tubular member, artery, vessel and bodily passable are usedinterchangeably throughout the specification.

An embodiment of invention is directed towards a catheter for insertioninto a subintimal space. The catheter includes a proximal end, a distalend, at least one lateral port, and at least one lumen for receiving aguide wire. The at least one lumen extends longitudinally through atleast the lateral port of the catheter. The catheter may also include anexchange port, e.g., RX port, arranged along an exterior portion of thecatheter body and configured to receive a second wire or guide wire. Theexchange port may be broken into two or more segments along the lengthof the catheter.

The catheter also includes a reentry member including at least one sharpsurface and configured to operate out of a portion of the lateral port.In one embodiment, the reentry member is configured with one or moresharp surfaces near its distal end, e.g., in a tear drop cross-sectionconfiguration. Alternatively, the cutting surface may extend along theentire surface of the reentry member or only a predetermined portion.Preferably, the cutting surface is configured to gain access from thesubintimal or interstitial region or space to the true lumen of thevessel. In one embodiment, the reentry member includes a lumen forreceiving a guide wire or supplemental treatment device. Thesesupplemental treatment devices may include guide wires, medicalinstruments, balloons, stents, laser catheters, optical fibers,visualization devices, medications and other medical instruments knownin the art. In a preferred embodiment, the lumen portion of the reentrymember is configured to receive a guide wire having a diameter in arange from about 0.01 inches to about 0.04 inches or larger.

In one embodiment, a catheter system includes a catheter body having aproximal end, a distal end, and at least one lumen wherein the lumenincludes a lateral opening. A reentry member including at least one voidspace or cut out that enables flexing is formed in at least a distalportion of the reentry member. The reentry member is configured to flexfrom a first a position to a second position upon application of a forceto a distal region of the reentry member.

In another embodiment, a reentry catheter for use in forming a pathwayin an interstitial space of an artery includes a catheter body includinga proximal end, a distal end, at least one lumen, and at least one port.An exchange port is arranged on at least a distal portion of thecatheter body. The exchange port includes at least one lumen configuredto receive a guidewire and the catheter body is configured to track overthe guidewire to a treatment site. A reentry member includes a proximalend and a distal end where distal end of the reentry member isconfigured to deploy through the at least one port from a first locationwithin the interstitial space of an artery to a second location within atrue lumen of the artery upon application of a substantially eccentricforce to a distal portion of the reentry member.

Another embodiment is directed towards a reentry catheter for use informing a pathway in an interstitial space of an artery. The reentrycatheter includes a catheter body having a proximal end, a distal end,at least one lumen, and at least one port. An exchange port is arrangedon at least distal portion of the catheter body. The exchange portincludes at least one lumen configured to receive a guidewire and thecatheter body is configured to track over the guidewire to a treatmentsite. The reentry member includes a proximal end, a distal end, at leastone lumen extending from the proximal end to the distal end. A tether orflexible tension member is coupled to a distal end portion of thereentry member. The tether is configured to deploy at least a portion ofthe reentry member through the at least one port from a first locationwithin the interstitial space of an artery to a second location within atrue lumen of the artery upon application of a force to the tether.

Suitable materials for the reentry member include but are not limited tosteel, alloys, nitinol, titanium, thermoplastics, including PEEK orpolyimide, and combinations thereof and the like. The reentry member mayalso be configured to have a predetermined shape, i.e., resilient shape,straight shape, curved shaped, memory shape, and combinations thereof.

In one embodiment, the reentry member is moveable, flexible and/orbendable from first configuration to a second configuration, e.g., aretracted position to an operative position. The movement may beachieved upon application of a force, e.g., an eccentric force appliedto a portion of the reentry member. In some embodiments, the force maybe generated with at least one of a tether; a control wire; a guide wirewith a hook; push member; pull member; ramp; wedge; balloon;electrically activated materials, including electroactive polymers,thermo-active polymers, electroactive metals and combinations thereof.

The electrically activated materials may be activated with an electricalsignal such as current or voltage as known in the art. For example, thecatheter body or the reentry member may be constructed as described inU.S. Pat. No. 7,951,186, which is hereby incorporated by reference.

In other embodiments, at least a portion of the reentry member may havea load or force built into the member. For example, the reentry membermay have pre-resilient shape and contained within a shroud or otherstructure that prevents movement. After the shroud or other structure isremoved, the reentry member is released from a first position to secondposition.

The catheter may be constructed from various materials as known in theart. For example, the catheter may be constructed from materials, suchas polyesters; polyurethanes; polyamides; polyolefins includingpolyethylene and polypropylene; and any copolymers thereof. Some morespecific examples of suitable materials include, but are not limited to:nylon; polyester elastomer; polyether/block polyamide, such as PEBAX,Hytrel, and/or Arnitel; polyamid such as Grilamid; flouro-polymer, suchas Kynar; polyether ether ketone (PEEK); polyethylene (PE);polyurethane; polyolefin copolymer (POC); tetrafluoroethylenes, such aspolytetrafluoroethylene (PTFE).

Other suitable materials include steel, including laser cut stainlesssteel. The catheter may comprise coils as described in FIG. 9C asdescribed in paragraphs [0101] and [0102] of U.S. Publication No.2010/0063534, which is hereby incorporated by reference as if fully setforth herein. The catheter may comprise at least one lumen that isconfigured to allow supplemental treatment devices access to theinterior of the lumen.

Another embodiment of the invention is directed towards a method forcrossing an obstruction in blood vessel. The method includes advancing afirst guide wire through a true lumen of vessel and into an interstitialspace of the vessel. In some instances with severe calcificationpresent, an undersized low profile balloon or other interventiondilation device may be used to pre-dilate the subintimal space prior tointroduction of the reentry catheter. Next, the reentry catheter isadvanced into the subintimal space through either an over the wire orvia a rapid exchange technique with the reentry member in a stowedposition. The catheter then advances through the subintimal space untilthe lateral port is distal to the total occlusion.

The orientation and the location of the catheter and its lateral portwith respect to the occlusion may be directed through the use ofradiopaque markers and visualization techniques known in the art. Oncethe catheter has been properly oriented, the operator moves the reentrymember from the stowed or locked position and subsequently articulatesthe member such that a precise incision is made between the subintimalspace and the true vessel lumen. A second interventional guide wire, inthe case of a rapid exchange catheter, or the first guide wire for anover the wire configuration is advanced into the vessel lumen throughthe hollow portion of the reentry member. Once the intervention wire isin place, the reentry member may be retracted and the entire reentrycatheter removed. Of course, more than one wire may also be used in theover the wire technique.

Yet another embodiment of the invention is directed towards a kit. Thekit includes a catheter according to embodiments of the invention andoptionally directions for use. The kit may also include a supplementaltreatment device, e.g., a balloon, optical catheter, visualizationcatheter, stent, embolic protection device and the like. In addition,the kit may include valves and other devices that may be used in medicalprocedures.

FIG. 1 illustrates an exemplary side view of a reentry catheteraccording to an embodiment of the invention.

Referring to FIG. 1, a reentry catheter according to this embodiment isgenerally depicted as reference number 100. The catheter 100 isconfigured to permit a user to cross an obstruction, e.g., partial ortotal occlusion, in a subintimal space of a vessel. The catheter 100also enables fast and simple true lumen reentry without the need foractive visualization, e.g., IVUS visualization. Visualization may beused to assist procedures of the invention, e.g., the visualization maybe active or passive. In one embodiment, visualization features areadded as described with reference towards U.S. Patent ApplicationPublication No. 2005/0171478, which is hereby incorporated by reference.

The catheter 100 is flexible and has a proximal end 102 and a distal end104. The proximal end 102 is attached to a handle (not shown). A shaft106 extends from the proximal end 102 of the catheter to the distal endof a rigid shroud or cover 108. The shaft 106 may be constructed ofconventional techniques. In a preferred embodiment, the shaft includesbraided, double braided, or by triplex construction as described in U.S.Patent Application No. 61/503,477, which is hereby incorporated byreference. A lateral port 110 is located near the distal end 104 andpreferably in the rigid shroud 108. Alternatively, or in addition to, alateral port (not shown) may also be located in the shaft 106. The shaft106 includes at least one lumen 114 extending at least partially alongthe entire shaft 106 and exiting out the catheter distal end 104. Insome embodiments, the lumen 114 may be used to provide supplementaltreatment devices to the distal tip of the catheter 100.

The distal end of shaft 106 is connected to the proximal end of shroud108 preferably by a laser weld, glue, over-molding or the like as knownin the art. There may be more than one lateral port at a distal portionof the shroud 108.

Optionally, a flexible atraumatic tip 116 may be attached to the distalend of the shroud 108 preferably by a laser weld, glue, over-molding orthe like as known in the art. Alternatively, the shroud or cover 108 mayextend to the catheter distal end 104 and be formed with an atraumatictip profile. Further, an over molded distal extension (not shown) of thecatheter may be incorporated to provide additional support during deviceorientation and during launch of the reentry member 112. The reentrymember 112 is docked in a straight position, as shown in FIG. 1 whiletraversing through an artery and into or reversed out of the subintimalvessel space. Alternatively, a retractable shroud or cover (not shown)may be used to protect the vessel during catheter transport through thebody.

At least one marker, e.g., a radiopaque marker, 118 is disposed on thebody of the catheter near its distal end or integrated within the bodyof the catheter. The radiopaque marker 118 is used with standardvisualization techniques, e.g. fluoroscopy, to guide the catheterthrough the body and into position in the subintimal space, to positionthe lateral port 110 and reentry member 112 at a desired location distalto the occlusion, and to determine whether the reentry member 12 is inthe stowed, ready, or in a fully articulated position. Radiopaquemarkers as described in U.S. Patent Application No. 61/503,477, U.S.Patent Application 2010/0317973, U.S. Pat. No. 6,544,230, U.S. Pat. No.6,719,725, or U.S. Pat. No. 6,231,546 may also be used, which are herebyincorporated by reference as if fully set forth herein.

The reentry member 112 may be configured to permit other devices orsupplemental devices to be operated through the lumen of the member 112.The supplemental devices may include a balloon, a cutting device,thrombectomy device, a guide wire, a filters, e.g., an embolic filter,optical devices, e.g., RF or laser ablation devices, combinations andthe like. In addition, the reentry member 112 may be configured to havea predetermined shape, i.e., pre-resilient shape, straight shape, curvedshaped, memory shape.

In a preferred embodiment, the lumen of the reentry member 112 is sizedto accommodate a wide range of guide wire diameters such as guide wirediameters in a range from about 0.01 inches to about 0.04 inches orlarger. Referring to FIG. 1, guide wire 120 is shown passing through alumen of the reentry member 112 in its stowed position and passingthrough the distal end 104 of the catheter as would be the case when thecatheter travels through the body and into or out of the subintimalspace.

FIG. 2A illustrates an exemplary bottom-profile view of the reentrymember illustrated in FIG. 1. FIG. 2B illustrates an exemplary side-viewof the reentry member illustrated in FIG. 1. FIG. 2C illustrates anexemplary end-view of the reentry member illustrated in FIG. 1.

Referring to FIGS. 2A-2C, reentry member 112 is constructed with atleast one void or cut geometry 124 that enables flexing. For example,when a force is placed at a distal region of the reentry member flexingor deflection of the distal region of the reentry may be achieved. Inthis embodiment, a diamond pattern 124 along the axis of the reentrymember 112 is formed at least along a distal region of the reentrymember 112. Though a diamond shape is illustrated in FIG. 2A, it isunderstood that the diamond shape may be any suitable geometric shape orcombination of different geometric shapes, e.g., squares, triangles,rectangles, ovals, circles, hexagons, octagons, pentagons, andcombinations thereof. Furthermore, the cut geometry 124 may be spaced atdifferent distances along the reentry member 112 and the number of cutgeometries 124 along the articulating cutting device may be varied. Asmore cut geometry 124 are used, it is easier to flex the reentry member112 upon application of a force.

At least one portion of the bottom distal edge of the reentry member 112is formed with a sharp leading edge 126. The reentry member 112 ishollow with a lumen 128 that is continuous with catheter lumen 114. Thecut out or void 124 may also be spaced at various locations around thecircumference of the reentry member 112 relative to a leading edge 126,e.g., about 2 degrees to about 180 degrees. In a preferred embodiment,the center of the cut out or void 124 is about 180 degrees relative to aleading edge 126. A sharp edge 156 at distal tip of the reentry member112 may also be utilized in this embodiment.

FIG. 3A illustrates an exemplary side view of the articulating cuttingdevice according to another embodiment of the invention. FIG. 3Billustrates an exemplary end view of the articulating cutting deviceaccording to FIG. 3A.

Referring to FIGS. 3A-3B, the reentry member 112 in this embodimentincludes a shaft or hollow tube with a bottom edge profile. The bottomedge profile may also contain void or cutout geometry 124 to provideflex or curvature during device reentry. At least a portion of thebottom distal edge of the reentry member 112 is formed with a sharpleading edge 126. The reentry member 112 is hollow with a circular lumen128 that is continuous with catheter lumen. An additional sharp edge 156is arranged at distal tip of the reentry member 112.

FIG. 4A illustrates a mechanism for controlling the reentry memberaccording to another embodiment of the invention. FIG. 4B illustrates amechanism of FIG. 4A for controlling the reentry member.

Referring to FIGS. 4A and 4B, a control wire 130 is coupled at an endregion 132 of the reentry member 112 along an axis eccentric to thelongitudinal axis of the device. In this embodiment, the control wire130 is coupled to an inside surface of the reentry member 112. Thecontrol wire 130 may be coupled to the reentry member by any suitabletechnique, including but not limited to bonding, welding, mechanicallycoupled or combinations thereof.

In another embodiment, the control wire 130 may be the guide wire 120configured to attach to distal portion of the reentry member 112, forexample with a hook on the end of the guide wire 120.

During reentry, an operator would mechanically control the reentrymember 112 by holding the catheter 100 in place and by pulling thecontrol wire 130 as shown with the arrow in FIG. 4B. The control wire130 is configured to transmit force from the proximal end of thecatheter 100 to articulating or flexing at least a portion of thereentry member 112. The eccentric location of the control wire 130 andthe placement of the coupled end 132 are such that a moment is createdon the device causing it to move from a first position in FIG. 4A to asecond position in FIG. 4B. This movement, bending or articulation isfrom an orientation of about parallel to the vessel wall to anorientation between about 0 and about 180 degrees of the vessel wall andmore preferably between about 5 and about 90 degrees with respect to thevessel wall and allowing the sharp edge 126 to penetrate the vesselwall.

The control wire may be comprised of at least one tendon, tether, coil,cable, linkage and made of a suitably flexible material capable ofwithstanding a high tension load such as Kevlar, Nylon, Nitinol,biocompatible metal wire, or other material known in the art.

FIGS. 5A-5B illustrate a mechanism for controlling the articulatingcutting device according to another embodiment of the invention.

Referring to FIGS. 5A-5B, a tether element 136 is coupled at a location132 near the distal end of the reentry member 112 and the tether element136 is coupled at proximal end of to the shroud 108 or catheter shaft106 at a point proximal to the most proximal void or cut out 134.

During reentry, an operator would control the reentry member 112 byholding the catheter 100 in place and pushing the reentry member 112 inthe direction of the arrow 140. The pushing force is configured toprovide the necessary force to curve or flex the distal end of reentrymember 112 from a first orientation, e.g., parallel to the vessel wallto a second orientation between about 0 and about 180 degrees of thevessel wall and more preferably between about 5 and about 90 degreeswith respect to the vessel wall. Thereby, allowing a leading edge 156 ofthe reentry member 112 to penetrate the vessel wall and reenter a truelumen of the vessel. Alternatively the control wire 130 in FIG. 4 or thetether 136 in FIG. 5 may be comprised of a pull cable or mechanicallinkage as known in the art. Optionally, mechanical advantage componentssuch as levers, manual gearing or electro-mechanical gearing may beincorporated near the proximal end of the catheter and more preferablyin the handle such that the reentry member 112 may be mechanicallycontrolled through a simple one-handed operation. In a preferredembodiment, the tether element 136 includes a rigid linkage is coupledto the proximal end of the element and coupled to a translating actuatoron a handle. Translational movement of the actuator would place thetether element in tension causing the reentry member to articulatethrough the lateral port. Alternatively, other actuating mechanisms suchas knobs, and the like, as known in the art can be utilized.

FIGS. 6A-6B illustrate a mechanism for controlling the reentry memberaccording to another embodiment of the invention.

Referring to FIGS. 6A-6B, the reentry member 112 is deployed with use ofelastomeric device, e.g., a balloon, located inside the distal portionof the catheter near the lateral port 110. The reentry member 112 isshown in stowed position in FIG. 6B. In a preferred embodiment, a highpressure, non-compliant balloon 142 is located in the distal end regionof the reentry catheter 100, preferably within the rigid shroud 108, andabove the lateral port opening 110 and the reentry member 112. Aninflation lumen 144 is in fluid communication with the deploymentballoon 142 and an inflation port 146 located along the shaft 106 at alocation proximal to the rigid shroud 108 or at or near a proximal hubthe catheter (not shown).

After inflation of the balloon 142 the reentry member 112 moves to asecond position or a non-stowed position. More specifically, thenon-compliant balloon 142 exerts an eccentric load on the top edge ofthe reentry member 112 to deliver the necessary force to curve or flexthe distal portion of the reentry member 112 from an orientation aboutparallel to the vessel wall to an orientation between about 0 and about180 degrees of the vessel wall and more preferably between about 5 andabout 90 degrees with respect to the vessel wall.

After articulated to a predetermined position, the entire catheter body,if necessary, may be pulled proximally causing the intimal tissue to beforced against the sharp leading edge 156 creating a subintimalarteriotomy. This action may be controlled mechanically using thecontrols integrated in the proximal handle (not shown). The distal tipof the reentry member 112 would then be inside the true lumen of thevessel and a guide wire 120 or supplementary intervention device may bepassed through the central lumen of the reentry member 112.

FIG. 7 illustrates an exemplary side view of a reentry catheteraccording to another embodiment of the invention. Referring to FIG. 7, areentry catheter according to this embodiment is generally depicted asreference number 200. An exchange port 222, e.g., rapid exchange port,is eccentrically located near the distal end of shaft 206. The exchangeport 222 may include a jacketed polyimide tube trimmed flush to theprofile of the device after processing to facilitate tracking and backloading of a first guide wire 220. The exchange port 222 may be sized toextend past a distal end of the catheter, be flush with the distal endof the catheter, or terminate a location proximal the distal end of thecatheter. Preferably, the guide wire 220 may have a diameter in a rangefrom about 0.01 inches to about 0.04 inches or greater and beconstructed of a range of materials as known in the art. In addition,the wire 220 may have lubricous coating, e.g., PVP thin film or PTFE,and/or a predetermined shape. Additionally, the wire 220 may be removedallowing supplemental treatment devices access to the distal tip of thecatheter. Additionally, the wire 220 may be removed allowingsupplemental treatment devices access to the distal tip of the catheter.The supplemental treatment devices include but are not limited to, guidewires, medical instruments, balloons, stents, laser catheters,medications, optical catheters and other medical instruments known inthe art

The catheter 200 is flexible and has a proximal end 202 and a distal end204. The proximal end 202 is attached to a handle (not shown). A shaft206 extends from the proximal end 202 of the catheter to the distal endof a rigid shroud 208. The shaft 206 may be constructed of conventionaltechniques, e.g. braided or double braided, or by triplex constructionas described herein. A lateral port 210 is located near the distal endand preferably in the rigid shroud 208. Alternatively, or in additionto, a lateral port (not shown) may also be located in the shaft 206. Theshaft 206 includes a lumen 214 extending at least partially along theentire shaft 206.

A reentry member 212 may be contained in the inner lumen of shaft 206along substantially the length of catheter 200. In some embodiments, thereentry member 212 is hollow and allows for an optional second guidewire, cannula or other supplemental treatment device 224. The distal end204 of shaft 206 is connected to the proximal end of shroud 208preferably by a laser weld, glue, over-molding or the like as known inthe art. There may be more than one lateral port at a distal portion ofthe shroud 208. Optionally, a flexible atraumatic tip 216 may beattached to the distal end of the shroud 208 preferably by a laser weld,glue, over-molding or the like as known in the art. Alternatively, theshroud 208 may extend to the catheter distal end 204 be formed with anatraumatic tip profile.

Further, an overmolded distal extension (not shown) of the catheter maybe added to a distal end of the catheter 200 as described in U.S. PatentApplication No. 61/503,477, which is hereby incorporated by reference asif fully set forth herein. The over molded distal extension isconfigured to provide additional support during device orientation andduring launch of the reentry member 212. The reentry member 212 isdocked in a straight position, while traversing through an artery andinto or out of the subintimal vessel space. Alternatively, a retractableshroud cover (not shown) may be used to protect the vessel duringcatheter transport through the body. The reentry member 212 may bemechanically controlled through the use of a tension member, a tethermember or a balloon as described herein. Optionally, an additional lumenmay be contained within the catheter 200 that may be used forsupplemental treatment devices.

The catheter 200 optionally may include at least one radiopaque marker218. In a preferred embodiment, the radiopaque markers are configured toensure orientation of the lateral port towards the true lumen of thevessel. The radiopaque markers may also be configured to determine aspatial relationship of other attributes of the catheter, e.g., thespatial location of the distal end of the catheter, confirmation of thestowed position of the reentry member, etc. In a preferred embodiment,at least one marker 218 is arranged near a distal portion of thecatheter.

FIGS. 8A-8H illustrates an exemplary method for using a medical deviceof FIG. 1 and FIG. 7.

Referring to FIGS. 8A-8E, a guide wire 802 is advanced to an occlusion806 in an attempt by the physician to cross the occlusion 806 to useconventional interventional devices such as laser atherectomy catheters,balloons, drug delivery devices, stents and the like. This advancementof the guide wire 802 is done in accordance with techniques known in thefield of cardiology, interventional radiology and the like. In someinstances, the physician is unable to cross through the lesion from theproximal lesion end to a point distal the lesion through the true lumenof the vessel. In these instances, as shown in FIG. 8A, the guide wire802 may unintentionally or intentionally enter the subintimal space 804after reaching the total occlusion 806. The guide wire 802 may includelubricious coating and have diameter in a range from about 0.01 inchesto about 0.04 inches or larger. In addition, the guide wire 802 may beshapeable, deformable, or have other attributes designed for crossing anocclusion 806 directly or indirectly.

Referring to FIG. 8B, after the guide wire 802 has reached thesubintimal space 804, a catheter 100 is advanced over the guide wire 802into the subintimal space 804. Alternatively for the embodiment shown inFIG. 7, reentry catheter 200 would advance through RX port 222 into thesubintimal space 804. Of course, any catheter described herein may alsobe used and reference to catheter 100 and 200 is done merely out ofconvenience. Next, the catheter 100 is advanced to a position distal ofthe occlusion 806.

Referring to FIG. 8C, the catheter 100 is oriented to position such thatthe lateral port 110 is distal the occlusion 806. In a preferredembodiment, the orientation of the catheter 100 may be conducted withutilization of the radiopaque markers 118 as described previously andwith reference to U.S. Patent Application No. 61/503,477, which ishereby incorporated by reference as if fully set forth herein. Forexample, in a preferred embodiment the catheter 100 is configured suchthat different views on fluoroscopic images enable the operator to alignthe lateral port 110 so that the reentry member 112 or other instrument,e.g., guide wire, working element, and the like, are aligned with a truelumen of the vessel. It is noted that other active or passivevisualization techniques as known in the art may also be utilized toorient the lateral port 110 with a true lumen. Other visualizationtechniques may also be used to aid in orientation includingincorporation of an active visualization element, such as an ultrasonictransducer or optical sensing element at a location either within the atleast one catheter lumen, on or within the catheter body, or on or nearthe lateral port.

Once the catheter 100 is in position at a location distal to theocclusion 806 and the lateral port 110 and the reentry member 112 areoriented to articulate and launch into the true vessel lumen, theoperator retracts the guide wire 802 to a position within the reentrymember, as shown in FIG. 8D. The operator would then transition thereentry member 112 from a stowed, safe position, to a ready position inpreparation for activation of the mechanical control for reentry.Alternatively this could involve refraction of a guard on the rigidshroud (not shown). Referring to FIG. 8E, reentry into the true vessellumen is accomplished by the operator holding the catheter in place andarticulating the reentry member 112 by either application of a tensionload as described in FIGS. 4A-4B, a push mechanism as described in FIGS.5A-5B or through inflation of an internal balloon as described in FIGS.6A-6B. In the alternative or in addition to, the activation mechanismmay be linked to a simple handle such that the operator either rotates aknob or activates a mechanical or electro-mechanical control element totransition from a ready to an articulated or flexed configuration. Theintervention guide wire 802 or another appropriate device may be passedthrough the shaft lumen 114 and the lumen 128 of the reentry member 112into the true vessel lumen.

Alternatively for a rapid exchange configuration as described in FIG. 7and FIG. 8F, retraction of guide wire 802 is not required. As with theprevious embodiment, the operator would transition the reentry member212 from a stowed, safe position, to a ready position in preparation foractivation of the mechanical control for articulation. Alternativelythis could involve retraction of a guard on the rigid shroud (notshown). Reentry into the true vessel lumen is accomplished by theoperator holding the catheter 200 in place and articulating the reentrymember 212 by techniques as described with regard to FIGS. 4A-4B, a pushmechanism as described with regard to FIGS. 5A-5B or through inflationof an internal balloon as described with regard to FIGS. 6A-6B.

The activation mechanism may be linked to a simple handle (not shown)such that the operator either rotates a knob or activates a mechanicalor electro-mechanical control element to transition from a ready to anarticulated of flexed configuration. The guide wire 802 or anotherappropriate device may be passed through the shaft lumen 214 and thelumen of the reentry member 212 and into the true vessel lumen. Theintervention guide wire may be sized from about 0.10 inches to about0.40 inches or larger and may contain a lubricous coating as known inthe art.

The reentry member 212 reenters the vessel lumen at an angle in a rangefrom about 5 degrees to about 180 degrees, more preferably at an anglein range from about between about 5 degrees to about 90 degrees. Thesharp edge 156 and/or 126 on the reentry member dissects the vessel wallfrom the subintimal space 804 into the true vessel lumen. The cuttingaction significantly reduces the force required to safely and accuratelyreenter the vessel lumen even in the presence of calcified tissue. Thisreentry force is significantly lower than the forces required for knownreentry devices, which require lateral extension of the catheter andimproved torsional control to support reentry forces. During reentry,the vessel wall tends to pull away from a more traditional reentrycannula tip during reentry such that penetration will require anincreased force application and possible multiple attempts tosuccessfully enter the lumen. The use of a reentry member overcomes thischallenge posed by the prior art and allows the operator to reenter attheir preferred location easily and repeatedly. Moreover, it is thoughtthat the use of the reentry member results in more consistent reentry ata location closer to the distal point of the occlusion 806 as comparedto the use of a simple curved cannula as known in the art.

Referring to FIGS. 8E-8H, after the proper reentry of the reentry member112 has been confirmed to be directed towards the true lumen of thevessel, another instrument, e.g., guide wire, working element, and thelike, exits the lateral port 110 and reenters the vessel. Once theintervention guide wire or intervention device is in position, thereentry member is retracted back into the lateral port 110 of thecatheter 100 and the catheter is removed as shown in FIG. 8H.Optionally, both the catheter 100 and guide wire 802 may be left inplace. Now that the total occlusion 806 is crossed variousinterventional procedures as known in the art may be performed. Forexample, a balloon catheter (not shown) may be used to dilate thesubintimal space along with possible stent placement (not shown) toprovide an alternative lumen through the subintimal space 804 and backinto the true vessel to restore adequate blood flow post-procedure.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A catheter system, comprising: a catheter body having a proximal end,a distal end, at least one lumen and a lateral opening; and a reentrymember comprising at least one void space in a circumferential portionof the reentry member that is configured to enable flexing from a firsta position to a second position when an axial eccentric load is placedat a distal portion of the reentry member.
 2. The catheter system ofclaim 1, wherein the axial eccentric load is applied with at least oneof a control wire, a cabling device, a ramp, and an elastomeric member.3. The catheter system of claim 1, wherein the reentry member comprisesa material selected from the group consisting of an electroactivepolymer, a thermo-active polymer, an electroactive metal andcombinations thereof.
 4. The catheter system of claim 3, wherein theaxial eccentric load is applied with an electrical signal applied to thereentry member.
 5. The catheter system of claim 1, wherein the reentrymember comprises a pre-resilient shape.
 6. The catheter of claim 1,wherein the reentry member comprises a material selected from the groupconsisting of stainless steel, nitinol, alloy, titanium, thermoplastics,polyether ether ketone (PEEK), polyimide, and combinations thereof. 7.The catheter of claim 1, wherein the catheter body further comprises asecond lumen, wherein the second lumen is configured to received a guidewire having a range from about 0.01 inches to about 0.04 inches.
 8. Thecatheter of claim 1, wherein the catheter body comprises a materialselected from the group consisting of a polyester, a polyurethane, apolyamide, a polyolefin, a polyethylene, a polypropylene, a nylon, apolyester elastomer, a polyether/block polyamide, a PEBAX, a Hytrel, anArnitel, a polyamide, a Grilamid, a flouro-polymer, a Kynar, polyetherether ketone, a polyethylene, a polyurethane, a polyolefin copolymer, atetrafluoroethylenes, a polytetrafluoroethylene, a steel, a laser cutstainless steel and combinations thereof.
 9. The catheter of claim 1,wherein the at least one lumen of the catheter body is configured toreceive a supplemental treatment device.
 10. The catheter of claim 9,wherein the supplemental treatment device is selected from the groupconsisting of a guide wire, a medical instrument, a balloon, a stent, alaser catheter, a medication, optical catheter and combinations thereof.11. The catheter of claim 1, further comprising at least one radiopaquemarker arranged on distal portion of at least one of a reentry memberand catheter body.
 12. The catheter of claim 1, wherein the at least onevoid space comprises a plurality of cut out sections.
 13. The catheterof claim 12, wherein the plurality of cut out sections comprise at leastone of the following geometrical configurations a tear dropconfiguration, a diamond configuration, a square configuration, apentagon configuration, a hexagon configuration and combinations of thesame.
 14. The catheter of claim 1, further comprising an exchange portarranged on at least distal portion of the catheter body, wherein theexchange port comprises at least one lumen configured to receive aguidewire and the catheter body is configured to track over theguidewire to a treatment site.
 15. A reentry catheter for use in forminga pathway in an interstitial space of an artery, comprising: a catheterbody including a proximal end, a distal end, at least one lumen, and atleast one port; an exchange port arranged on at a least distal portionof the catheter body, wherein the exchange port comprises at least onelumen configured to receive a guidewire and the catheter body isconfigured to track over the guidewire to a treatment site; a reentrymember having a proximal end, a distal end, at least one lumen extendingfrom the proximal end to the distal end, wherein the distal end includesa portion having a sharp surface to permit cutting, and wherein thereentry member is configured to be slidably advanced within the at leastone lumen of the catheter body; and a tether coupled to a distal endportion of the reentry member, wherein a distal end portion of thereentry member is configured to deploy through the at least one portfrom a first location within the interstitial space of the artery to asecond location within a true lumen of the artery upon application of aforce to the tether.
 16. A method of crossing an obstruction in a bloodvessel, comprising the steps of: advancing a first guide wire into alumen of the vessel towards the obstruction in the vessel; advancing thefirst guide wire into a subintimal space of the vessel to a locationdistal of the obstruction; advancing a catheter comprising reentrymember over the guide wire to a location where a port of the catheter isat a location distal of the obstruction; and cutting with the reentrymember from a first location within the subintimal space of the arteryto a second location within a true lumen of the vessel.
 17. The methodof claim 13, further comprising the steps of: returning the reentrymember from the second location to the first location; and removing thereentry catheter from the vessel.
 18. The method of claim 13, whereinthe cutting step comprises inflating an elastomeric member.
 19. Themethod of claim 16, wherein the cutting step comprises applying anelectrical signal to the reentry member.
 20. The method of claim 13,wherein the cutting step comprises applying a force to a control wire,cable, or tether element.